error[E0521]: borrowed data escapes outside of closure
 --> tests/ui/test_client_cannot_be_smuggled_out.rs:9:31
  |
6 |     Client::new(|client, _| {
  |                  ------
  |                  |
  |                  `client` is a reference that is only valid in the closure body
  |                  has type `&mut Client<'1>`
...
9 |         let smuggled_client = std::mem::replace(client, other_client);
  |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |                               |
  |                               `client` escapes the closure body here
  |                               argument requires that `'1` must outlive `'static`
  |
  = note: requirement occurs because of a mutable reference to `Client<'_>`
  = note: mutable references are invariant over their type parameter
  = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance